Heretofore, carton end panel folding arrangements for folding the trailing panel of moving open-ended cartons have generally involved somewhat complex structures including many different components to accomplish the folding operation.
For example, Linner U.S. Pat. No. 4,092,906 includes a pair of oppositely rotating pins for engaging and folding front and rear flaps extending from boxes, the pins being driven by a plurality of cooperating gear wheels.
Bombard U.S. Pat. No. 2,883,917 illustrates a method and apparatus for folding trailing flaps as blanks travel in a straight line path through the machine. The apparatus includes a rotatable member having circumferential flap recesses formed therein and fingers with hooks extending substantially tangentially therefrom. While the conveyor pauses, the rotating hooks engage each trailing flap in turn and folds it forwardly through the adjacent flap recess.
Eldridge U.S. Pat. No. 4,432,745 discloses an apparatus for folding the trailing edge of paperboard blanks wherein arms with heads formed thereon rotate relative to a conveyor carrying the blanks such that the heads, while rotating, extend through openings in the conveyor to contact the trailing flaps of the blanks and fold them forwardly onto the respective blank bodies.
Toriyama U.S. Pat. No. 4,629,445 employs a rotatable claw mechanism for folding a rear portion of a blank, with an associated cam mechanism for changing the angular speed of the claw mechanism.
Genoud et al U.S. Pat. No. 4,747,813 discloses a further rotating arm and nose portion for engaging and folding a trailing flap as a blank moves along its path.
Zak U.S. Pat. No. 4,539,002 and Nava U.S. Pat. No. 4,119,018 each include two-blade units serving to fold the trailing flap only; and Theys et al U.S. Pat. No. 3,587,411 discloses oppositely disposed two-blade units for progressively folding two side panels and a front panel.
Zimmer et al U.S. Pat. No. 3,602,107 and Grulich et al U.S. Pat. No. 3,501,889 each include four-blade units, with Zimmer et al requiring two four-blade units to close the leading and trailing carton flaps, and Grulich et al's four-blade unit merely collapses a side of a cylindrical belt.
Murrah U.S. Pat. No. 4,990,128 discloses a single freely rotatable roller which serves to first fold rearwardly the leading panel of a tubular carton mounted on a rotating mandrel, and then to engage and fold the trailing panel forwardly as the carton rotates therepast.